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<html>

<head>
<meta http-equiv="Content-Language" content="en-us">
<link rel="stylesheet" type="text/css" href="../stylesheets/style.css">
<title>Link Task</title>
</head>

<body>

<h2 id="link">Link</h2>
<p><em>Since Apache Ant 1.10.6</em></p>

<h3>Description</h3>
<p>Assembles jmod files into an executable image.  Equivalent to the JDK's
<a href="https://docs.oracle.com/en/java/javase/11/tools/jlink.html">jlink</a>
tool.
</p>
<p>Requires Java 9 or later.</p>

<h3>Parameters</h3>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>destDir</td>
    <td>Root directory of created image.</td>
    <td>Yes</td>
  </tr>
  <tr>
    <td>modulepath</td>
    <td>Path-like sequence of jmod files to link in order to create image.</td>
    <td rowspan="2">One of these is required, unless a nested
        <code>&lt;modulepath&gt;</code> is present.</td>
  </tr>
  <tr>
    <td>modulepathref</td>
    <td class="left">Path-like sequence of jmod files to link in order to
        create image, given as a <a href="../using.html#references">reference</a>
        to a path defined elsewhere.</td>
  </tr>
  <tr>
    <td>modules</td>
    <td>Comma-separated list of modules to place in the linked image.</td>
    <td>Yes, unless one or more nested <code>&lt;module&gt;</code> elements
        are present.</td>
  </tr>
  <tr>
    <td>observableModules</td>
    <td>Comma-separated list of explicit modules that comprise
        "universe" visible to link tool while linking.</td>
    <td>No</td>
  </tr>
  <tr>
    <td>launchers</td>
    <td>Comma-separated list of commands, each of the form
        <var>name</var><code>=</code><var>module</var> or
        <var>name</var><code>=</code><var>module</var><code>/</code><var>mainclass</var></td>
    <td>No</td>
  </tr>
  <tr>
    <td>locales</td>
    <td>Comma-separated list of extra locales, or wildcard patterns matching
        multiple locale names, to include.
        Requires <code>jdk.localedata</code> module.</td>
    <td>No</td>
  </tr>
  <tr>
    <td>excludeResources</td>
    <td>Comma-separated list of patterns specifying resources to exclude
        from source jmods.  Each is either a
        <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/nio/file/FileSystem.html#getPathMatcher%28java.lang.String%29">standard PathMatcher pattern</a>
        or <code>@</code><var>filename</var>, indicating a text file with
        one resource name per line.</td>
    <td>No</td>
  </tr>
  <tr>
    <td>excludeFiles</td>
    <td>Comma-separated list of patterns specifying files to exclude
        from linked image.  Each is either a
        <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/nio/file/FileSystem.html#getPathMatcher%28java.lang.String%29">standard PathMatcher pattern</a>
        or <code>@</code><var>filename</var>, indicating a text file with
        one file name per line.</td>
    <td>No</td>
  </tr>
  <tr>
    <td>resourceOrder</td>
    <td>Comma-separated list of patterns specifying resource search order.
        Each is either a
        <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/nio/file/FileSystem.html#getPathMatcher%28java.lang.String%29">standard PathMatcher pattern</a>
        or <code>@</code><var>filename</var>, indicating a text file with
        one resource name per line.</td>
    <td>No</td>
  </tr>
  <tr>
    <td>bindServices</td>
    <td>Boolean, whether to include in linked image any service providers
        found in module path corresponding to service provider interfaces
        used by explicitly linked modules.</td>
    <td>No, default is false</td>
  </tr>
  <tr>
    <td>ignoreSigning</td>
    <td>Boolean, whether to allow signed jar files.
        (Note: As of Java 11, this is ignored and is always treated as true.)</td>
    <td>No, default is false</td>
  </tr>
  <tr>
    <td>includeHeaders</td>
    <td>Boolean, whether to include header files in linked image.</td>
    <td>No, default is true</td>
  </tr>
  <tr>
    <td>includeManPages</td>
    <td>Boolean, whether to include man pages in linked image.</td>
    <td>No, default is true</td>
  </tr>
  <tr>
    <td>includeNativeCommands</td>
    <td>Boolean, whether to include native executables in linked image.</td>
    <td>No, default is true</td>
  </tr>
  <tr>
    <td>debug</td>
    <td>Boolean, whether to include debug information.</td>
    <td>No, default is true</td>
  </tr>
  <tr>
    <td>verboseLevel</td>
    <td>If set, the linker will produce verbose output, which will be logged at
        the specified Ant log level (<code>DEBUG</code>, <code>VERBOSE</code>,
        <code>INFO</code>, <code>WARN</code>, or <code>ERR</code>).</td>
    <td>No, default is no verbose output</td>
  </tr>
  <tr>
    <td>compress</td>
    <td>Compression level of linked image. One of:
        <dl>
        <dt><code>0</code> or
            <code>none</code></dt>
        <dd>no compression (default)</dd>
        <dt><code>1</code> or
            <code>strings</code></dt>
        <dd>constant string sharing</dd>
        <dt><code>2</code> or
            <code>zip</code></dt>
        <dd>zip compression</dd>
        </dl>
    </td>
    <td>No, default is no compression</td>
  </tr>
  <tr>
    <td>endianness</td>
    <td>Byte order of linked image, must be <code>little</code> or <code>big</code>
    <td>No, default is native byte order</td>
  </tr>
  <tr>
    <td>checkDuplicateLegal</td>
    <td>Boolean.  When merging legal notices from different modules
        because they have the same name, verify that their contents
        are identical.</td>
    <td>No, default is false, which means any license files
        with the same name are assumed to have the same content, and no
        checking is done.</td>
  </tr>
  <tr>
    <td>vmType</td>
    <td>Hotspot VM in image. One of:
        <ul>
        <li><code>client</code>
        <li><code>server</code>
        <li><code>minimal</code>
        <li><code>all</code>
        </ul>
    </td>
    <td>No, default is <code>all</code></td>
  </tr>
</table>

<h3>Parameters specified as nested elements</h3>

<p><code>&lt;link&gt;</code> can have the following nested elements:</p>
<ul>
<li><a href="#nested-modulepath">modulepath</a></li>
<li><a href="#nested-module">module</a></li>
<li><a href="#nested-observableModule">observableModule</a></li>
<li><a href="#nested-launcher">launcher</a></li>
<li><a href="#nested-locale">locale</a></li>
<li><a href="#nested-resourceOrder">resourceOrder</a></li>
<li><a href="#nested-excludeResources">excludeResources</a></li>
<li><a href="#nested-excludeFiles">excludeFiles</a></li>
<li><a href="#nested-compress">compress</a></li>
<li><a href="#nested-releaseInfo">releaseInfo</a></li>
</ul>

<h4 id="nested-modulepath">modulepath</h4>
<p><a href="../using.html#path">Path-like structure</a> pointing to
    jmod files to link into image.</p>

<h4 id="nested-module">module</h4>
<p>Names a single module to be placed in the linked image.  This may be
specified multiple times.</p>
<p>Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>name</td>
    <td>Name of module to add.</td>
    <td>Yes</td>
  </tr>
</table>

<h4 id="nested-observableModule">observableModule</h4>
<p>Names a module visible to the linking process, instead of every module
in the module path being considered.  This may be specified multiple times.
<p>Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>name</td>
    <td>Name of module to add to list of observable modules.</td>
    <td>Yes</td>
  </tr>
</table>

<h4 id="nested-launcher">launcher</h4>
<p>Specifies an executable file which will be added to the linked image,
which executes a particular module's main class.  Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>name</td>
    <td>Name of launcher.  This typically is used for the name of the
        executable file.</td>
    <td>Yes</td>
  </tr>
  <tr>
    <td>module</td>
    <td>Name of module to execute.</td>
    <td>Yes</td>
  </tr>
  <tr>
    <td>mainClass</td>
    <td>Name of entry point class in module to execute.</td>
    <td>Required unless module has its own main class defined.</td>
  </tr>
</table>

<h4 id="nested-locale">locale</h4>
<p>Specifies locales to include in linked image.  May be specified multiple
times.  Requires <code>jdk.localedata</code> module.  Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>name</td>
    <td>Name of locale, or wildcard pattern with <q><code>*</code></q>
        that matches multiple locale names.</td>
    <td>Yes</td>
  </tr>
</table>

<h4 id="nested-resourceOrder">resourceOrder</h4>
<p>Explicit resource search order in linked image.  May be specified multiple
times.  Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>pattern</td>
    <td>A <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/nio/file/FileSystem.html#getPathMatcher%28java.lang.String%29">standard PathMatcher pattern</a>
        for matching resources</td>
    <td rowspan="2">Exactly one of these</td>
  </tr>
  <tr>
    <td>listFile</td>
    <td class="left">Text file containing list of resource names (not patterns),
        one per line</td>
  </tr>
</table>

<p>If the <code>resourceOrder</code> attribute is also present on the task, its
patterns are treated as if they occur before patterns in nested
<code>&lt;resourceOrder&gt;</code> elements.</p>

<h4 id="nested-excludeResources">excludeResources</h4>
<p>Excludes files from linked image tree.  May be specified multiple times.
   Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>pattern</td>
    <td>A <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/nio/file/FileSystem.html#getPathMatcher%28java.lang.String%29">standard PathMatcher pattern</a>
        for matching resources</td>
    <td rowspan="2">Exactly one of these</td>
  </tr>
  <tr>
    <td>listFile</td>
    <td class="left">Text file containing list of resource names (not patterns),
        one per line</td>
  </tr>
</table>

<h4 id="nested-excludeFiles">excludeFiles</h4>
<p>Excludes files from linked image.  May be specified multiple times.
   Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>pattern</td>
    <td>A <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/nio/file/FileSystem.html#getPathMatcher%28java.lang.String%29">standard PathMatcher pattern</a>
        for matching files</td>
    <td rowspan="2">Exactly one of these</td>
  </tr>
  <tr>
    <td>listFile</td>
    <td class="left">Text file containing list of file names (not patterns),
        one per line</td>
  </tr>
</table>

<h4 id="nested-compress">compress</h4>
<p>Describes how image should be compressed.  Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>level</td>
    <td>Compression level of linked image. One of:
        <dl>
        <dt><code>0</code> or
            <code>none</code></dt>
        <dd>no compression (default)</dd>
        <dt><code>1</code> or
            <code>strings</code></dt>
        <dd>constant string sharing</dd>
        <dt><code>2</code> or
            <code>zip</code></dt>
        <dd>zip compression</dd>
        </dl>
    </td>
    <td>Yes</td>
  </tr>
  <tr>
    <td>files</td>
    <td>Comma-separated list of patterns matching files to compress.
        Each pattern either a
        <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/nio/file/FileSystem.html#getPathMatcher%28java.lang.String%29">standard PathMatcher pattern</a>
        or <code>@</code><var>filename</var>, indicating a text file with
        one file name per line.</td>
    <td>No</td>
  </tr>
</table>

<p><code>&lt;compress&gt;</code> can also have any number of nested
<code>&lt;files&gt;</code> elements, with these attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>pattern</td>
    <td>A <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/nio/file/FileSystem.html#getPathMatcher%28java.lang.String%29">standard PathMatcher pattern</a>
        for matching files</td>
    <td rowspan="2">Exactly one of these</td>
  </tr>
  <tr>
    <td>listFile</td>
    <td class="left">Text file containing list of file names (not patterns),
        one per line</td>
  </tr>
</table>

<h4 id="nested-releaseInfo">releaseInfo</h4>
<p>Replaces, augments, or trims the image's release info properties.
Can be specified multiple times.  Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>file</td>
    <td>Java properties file containing new release info properties
        that will entirely replace the current ones.</td>
    <td>No</td>
  </tr>
  <tr>
    <td>delete</td>
    <td>Comma-separated property keys to remove from application's
        release info
    <td>No</td>
  </tr>
</table>

<p><code>&lt;releaseInfo&gt;</code> can also have any number of these nested elements:</p>
<h5>add</h5>
<p>Specifies additional release info properties.  Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>key</td>
    <td>Key of single property to add.</td>
    <td rowspan="2">Yes, unless <code>file</code> is specified</td>
  </tr>
  <tr>
    <td>value</td>
    <td class="left">Value of single property to add.</td>
  </tr>
  <tr>
    <td>file</td>
    <td>Java property file containing any number of properties to add.</td>
    <td>Yes, unless <code>key</code> and <code>value</code> are specified</td>
  </tr>
  <tr>
    <td>charset</td>
    <td>Character set of property file.</td>
    <td>No, default is <code>ISO_8859_1</code>, in accordance with
        java.util.Properties class.</td>
  </tr>
</table>

<h5>delete</h5>
<p>Property keys to remove from applicaiton's release info.  Attributes:</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>key</td>
    <td>Key of property to remove.</td>
    <td>Yes</td>
  </tr>
</table>

<h3>Examples</h3>
<h4>Basic linking</h4>
<pre>
&lt;jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/&gt;
&lt;link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp"/&gt;
</pre>

<h4>Custom binaries</h4>
<p>This will cause a <samp>bin/MyEditor</samp> script to appear in the
image:
<pre>
&lt;jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/&gt;
&lt;link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp"
      launchers="MyEditor=com.example.myapp/com.example.myapp.editors.EditorMain"/&gt;
</pre>

<p>Same thing, using a nested launcher element:</p>
<pre>
&lt;jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/&gt;
&lt;link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp"&gt;

    &lt;launcher name="MyEditor" module="com.example.myapp"
              mainClass="com.example.myapp.editors.EditorMain"/&gt;

&lt;/link&gt;
</pre>

<h4>Limiting locales</h4>
<p>Include just the locales needed by the application from the <a href="https://docs.oracle.com/en/java/javase/11/docs/api/jdk.localedata/module-summary.html">jdk.localedata</a> module:</p>
<pre>
&lt;jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/&gt;
&lt;link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp,jdk.localedata"
      locales="zh,jp-*"/&gt;
</pre>

<h4>Compressed image</h4>
<p>Compress entire image:</p>
<pre>
&lt;jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/&gt;
&lt;link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp,jdk.localedata"
      compress="zip"/&gt;
</pre>

<p>Compress only some files in the image:</p>
<pre>
&lt;jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/&gt;
&lt;link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp,jdk.localedata"&gt;

    &lt;compress level="zip" files=".*\.xml"/&gt;

&lt;/link&gt;
</pre>

<h4>Cross-compiling</h4>
<p>To create an image for a different platform:

<ul>
<li>Download the JDK for that platform, and expand the archive manually into
a directory of your choice.  (Downloading a zip or tar.gz version of a JDK
instead of an installer will make this easier.)</li>
<li>Determine the foreign JDK's platform string.  This can be done with
a command that examines the JDK's <samp>jmods/java.base.jmod</samp> file:
<pre>
jmod describe "$FOREIGN_JDK_HOME"/jmods/java.base.jmod | grep '^platform'
</pre>
</li>
<li>Create your jmod using the foreign JDK's platform string:
<pre>
&lt;jmod destfile="MyApp.jmod" classpath="build/myapp.jar" platform="windows-amd64"/&gt;
</pre>
</li>
<li>Link with the foreign JDK's <samp>jmods</samp> directory in the module path:
<pre>
&lt;link destDir="build/image"
      modulepath="MyApp.jmod;${foreign-jdk-home}/jmods"
      modules="com.example.myapp"/&gt;
</pre>
</li>
</ul>

</body>
</html>
